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smbpasswd(5)





NAME

       smbpasswd - The Samba encrypted password file


SYNOPSIS

       smbpasswd


DESCRIPTION

       This tool is part of the samba(7) suite.

       smbpasswd is the Samba encrypted password file. It contains the
       username, Unix user id and the SMB hashed passwords of the user, as
       well as account flag information and the time the password was last
       changed. This file format has been evolving with Samba and has had
       several different formats in the past.


FILE FORMAT

       The format of the smbpasswd file used by Samba 2.2 is very similar to
       the familiar Unix passwd(5) file. It is an ASCII file containing one
       line for each user. Each field ithin each line is separated from the
       next by a colon. Any entry beginning with '#' is ignored. The smbpasswd
       file contains the following information for each user:

       name
           This is the user name. It must be a name that already exists in the
           standard UNIX passwd file.

       uid
           This is the UNIX uid. It must match the uid field for the same user
           entry in the standard UNIX passwd file. If this does not match then
           Samba will refuse to recognize this smbpasswd file entry as being
           valid for a user.

       Lanman Password Hash
           This is the LANMAN hash of the user's password, encoded as 32 hex
           digits. The LANMAN hash is created by DES encrypting a well known
           string with the user's password as the DES key. This is the same
           password used by Windows 95/98 machines. Note that this password
           hash is regarded as weak as it is vulnerable to dictionary attacks
           and if two users choose the same password this entry will be
           identical (i.e. the password is not "salted" as the UNIX password
           is). If the user has a null password this field will contain the
           characters "NO PASSWORD" as the start of the hex string. If the hex
           string is equal to 32 'X' characters then the user's account is
           marked as disabled and the user will not be able to log onto the
           Samba server.

           WARNING !!  Note that, due to the challenge-response nature of the
           SMB/CIFS authentication protocol, anyone with a knowledge of this
           password hash will be able to impersonate the user on the network.
           For this reason these hashes are known as plain text equivalents
           and must NOT be made available to anyone but the root user. To
           protect these passwords the smbpasswd file is placed in a directory
           with read and traverse access only to the root user and the
           smbpasswd file itself must be set to be read/write only by root,
           with no other access.

       NT Password Hash
           This is the Windows NT hash of the user's password, encoded as 32
           hex digits. The Windows NT hash is created by taking the user's
           password as represented in 16-bit, little-endian UNICODE and then
           applying the MD4 (internet rfc1321) hashing algorithm to it.

           This password hash is considered more secure than the LANMAN
           Password Hash as it preserves the case of the password and uses a
           much higher quality hashing algorithm. However, it is still the
           case that if two users choose the same password this entry will be
           identical (i.e. the password is not "salted" as the UNIX password
           is).

           WARNING !!. Note that, due to the challenge-response nature of the
           SMB/CIFS authentication protocol, anyone with a knowledge of this
           password hash will be able to impersonate the user on the network.
           For this reason these hashes are known as plain text equivalents
           and must NOT be made available to anyone but the root user. To
           protect these passwords the smbpasswd file is placed in a directory
           with read and traverse access only to the root user and the
           smbpasswd file itself must be set to be read/write only by root,
           with no other access.

       Account Flags
           This section contains flags that describe the attributes of the
           users account. This field is bracketed by '[' and ']' characters
           and is always 13 characters in length (including the '[' and ']'
           characters). The contents of this field may be any of the following
           characters:

           o   U - This means this is a "User" account, i.e. an ordinary user.

           o   N - This means the account has no password (the passwords in
               the fields LANMAN Password Hash and NT Password Hash are
               ignored). Note that this will only allow users to log on with
               no password if the
                null passwords parameter is set in the smb.conf(5) config
               file.

           o   D - This means the account is disabled and no SMB/CIFS logins
               will be allowed for this user.

           o   X - This means the password does not expire.

           o   W - This means this account is a "Workstation Trust" account.
               This kind of account is used in the Samba PDC code stream to
               allow Windows NT Workstations and Servers to join a Domain
               hosted by a Samba PDC.

           Other flags may be added as the code is extended in future. The
           rest of this field space is filled in with spaces. For further
           information regarding the flags that are supported please refer to
           the man page for the pdbedit command.

       Last Change Time
           This field consists of the time the account was last modified. It
           consists of the characters 'LCT-' (standing for "Last Change Time")
           followed by a numeric encoding of the UNIX time in seconds since
           the epoch (1970) that the last change was made.

       All other colon separated fields are ignored at this time.


VERSION

       This man page is correct for version 3.0 of the Samba suite.


SEE ALSO

       smbpasswd(8), Samba(7), and the Internet RFC1321 for details on the MD4
       algorithm.


AUTHOR

       The original Samba software and related utilities were created by
       Andrew Tridgell. Samba is now developed by the Samba Team as an Open
       Source project similar to the way the Linux kernel is developed.

       The original Samba man pages were written by Karl Auer. The man page
       sources were converted to YODL format (another excellent piece of Open
       Source software, available at ftp://ftp.icce.rug.nl/pub/unix/) and
       updated for the Samba 2.0 release by Jeremy Allison. The conversion to
       DocBook for Samba 2.2 was done by Gerald Carter. The conversion to
       DocBook XML 4.2 for Samba 3.0 was done by Alexander Bokovoy.

Samba 3.0                         05/28/2008                      SMBPASSWD(5)

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